Effect of Post Weld Heat Treatment Process on Microstructure and Mechanical Properties of Friction Welded Dissimilar Drill Pipe

Abstract

In this study, N80-42CrMo4 dissimilar drill pipes were welded by a roto-friction welding machine. A set of welded samples were tested as-welded condition. Another set of welded samples were post weld heat treated (stress relief annealing) at the temperature of 600 °C, for 20 min. and then tested. The microstructures of the as-welded and stress relief annealed samples were examined by optical microscope and SEM. The properties of the all welded samples were determined by hardness measurement, tension and V notch-impact tests. The high hardness especially in the weld interface resulted in low toughness. As a conclusion, the stress relief annealing treatment caused a little decrease in yield strength and ultimate tensile strength, but increase in the elongation. The ductility of samples also increased after annealing treatment which is very important for static and dynamic loads.

Effects of post-weld heat treatments on the microstructure, mechanical and corrosion properties of gas metal arc welded 304 stainless steel

“…Post-annealing of the weldment resulted in $5 per cent reduction in the tensile strength and $20 per cent increase in elongation when compared with the as-welded sample. The reduction in the tensile strength after post-annealing process was earlier reported by Emre and Kacar (2015) while studying the effects of PWHT on the mechanical properties of dissimilar friction stir welded N80 grade steel and 42CrMo4 grade medium-carbon steel. However, the tempered sample showed significant improvement in both the tensile strength and elongation (i.e.…”

Influence of heat treatment on friction-welded joints made of high-carbon high-chromium tool steel/low-carbon steel for tooling applications

“…Heat treatment was carried out on welded specimens in order to relieve stresses and to enhance the uniformity of microstructure in the welded region. Justifying the recommended temperature ranges given in [5,11] and material vendor indicating heating temperature of 871 °C, holding time of 1 h per 25-mm thickness, and furnace cooling, one set of the welded specimens (S1) was gradually postheat-treated at 800 °C within 30 min and furnace cooled. Another set of welded specimens (S2) was not heat treated.…”

“…and increase toughness. Either annealing and normalizing or tempering has been tried by many researchers [4][5][6][7][8].…”

“…In the studies by Raja Sekhar [4], friction-welded component of AISI 431 martensitic stainless was post-tempered at 400 °C and it is reported that martensitic microstructure got coarsened which resulted in high strength and hardness but the poor impact toughness. Emre and Kacar [5] conducted friction welding studies with pipes made of N80 and 42CrMo4 steels and recommended annealing at 600 °C for 20 min. The heat treatment process minimized residual stress in the hard martensite phase without much decrease in mechanical strength.…”

Fatigue strength of 30ХГСА–40ХМФА welded joints produced by rotary friction welding

“…Как правило, бурильные трубы представляют собой сварную конструкцию замковой части с телом трубы из средне-и низкоуглеродистых легированных сталей, соединенную посредством РСТ 1 . В качестве тела трубы для облегченных конструкций бурильных труб предполагается использовать трубную заготовку из стали 30ХГСА, которая после закалки и отпуска обеспечивает необходимые свойства: условный предел текучести ≥750 МПа, временное сопротивление ≥850 МПа, относительное удлинение ≥12 %.…”